Electric vehicles, hybrid vehicles and other electric motored vehicles are gaining large attention as ecologically friendly vehicles. These vehicles have mounted therein an electric motor generating force to drive and thus cause the vehicle to travel, and a rechargeable power storage device storing therein electric power supplied to the electric motor. Note that hybrid vehicles include a vehicle having mounted therein an electric motor and in addition an internal combustion engine together therewith as power sources, and a vehicle having mounted therein a power storage device and in addition a fuel cell together therewith as direct current power supplies for driving the vehicle.
A hybrid vehicle is also known that, as well as an electric vehicle, allows a power supply external to the vehicle to charge a power storage device mounted in the vehicle. For example, a plug-in hybrid vehicle is known. This vehicle allows the power storage device to be charged from a general household power supply through a charging cable connecting a receptacle of a power supply provided in premises and a charging port of the vehicle.
On the other hand, an electric power transfer method without using a power supply cord or an electric power transfer cable, i.e., wireless power transfer, is gaining attention in recent years. There are three wireless electric power transfer techniques known as being promising, which are power transfer through electromagnetic induction, power transfer by microwaves, and power transfer through resonance.
Of these three techniques, power transfer through resonance causes a pair of resonators (e.g., a pair of self resonant coils) to resonate in an electromagnetic field (a near field) to transfer electric power through the electromagnetic field in a non-contact manner, and can transfer large electric power of several kW over a relatively large distance (e,g., of several meters (see Patent Document 1 and Non Patent Document 1 for example).
Citation List
Patent Literature
PTL 1: WO2007/008646
Non Patent Literature
NPL 1: Andre Kurs et al., “Wireless Power Transfer via Strongly Coupled Magnetic Resonances”, [online], Jul. 6, 2007, Science, volume 317, pp. 83-86, [searched on Aug. 17, 2007], Internet <URL:http://www.sciencemag.org/cgi/reprint/317/5834/83.pdf>